The present invention relates to a new and improved method of, and apparatus for, the degermination of water utilizing the principle of exposing the water to be degerminated to the action of air ions.
The proposed method is especially, however not exclusively, applicable for the degermination of water intended to be used for swimming pools or the like or water delivered from water tanks or containers and intended for use as drinking water.
Therefore, in the context of this disclosure there should be understood the expression "degermination" not merely the attainment of an absolutely germless condition, rather, and especially, also a considerable reduction in the number of germs contained in the water to be degerminated. Further, the term "germ," either in the singular or plural, is intended to encompass bacteria and other micro-organisms which are to be removed from the treated water and can be eliminated by the teachings of the invention.
A review of the heretofore known techniques for the degermination of water permits classification thereof into three different groups.
The first group encompasses the most widespread method which resides in introducing bactericide chemicals into the water to be degerminated, for instance chlorine gas or compounds releasing chlorine gas, bromine and/or ozone. These chemicals are added to the water to be freed of germs or also, for instance, formed in the water itself by electrolytic processes by utilizing special electrode materials. After degermination chemical residues remain in the water which, depending upon the intended use of such water, can be removed during a further working step.
The second group, which is less frequently employed, relies upon the principle of so-to-speak mechanically removing germs. Belonging to such method are those wherein the water to be degerminated is exposed to ultra filtration.
The third group of prior art water degermination methods contemplates exposing the water to be degerminated to the action of air ions. Such method is disclosed, for instance, in Swiss Pat. No. 444,065. This state-of-the-art method relates to the post-treatment of pre-clarified waste water by gasification and contemplates gasifying the pre-clarified waste water with an ionized, oxygen-containing gaseous mixture during such time as the water is conducted in a state of turbulent flow through a closed conduit. This heretofore known method strives for oversaturation of the treated water with ions having an affinity for oxidation and produced by ionization, for instance activated oxygen or ozone, and contemplates accelerating the decomposition (oxidation) of the organic contaminants contained in the water. The thus resulting degermination action of the ozone constitutes an apparently not undesired side effect.
Although the bacteriostatic effect of air ions is disputed, the bactericide effect of such air ions was heretofore not known; in fact the same was even refuted.
This presumption was obvious since notwithstanding the frequent use of such terms as "ionized air" or "active air" in relevant publications, the corresponding tests were not carried out with pure air ions, rather always essentially with ozone (O.sub.3), the bactericide effect of which was not in dispute.
In Swiss Pat. No. 524,112, which essentially corresponds to U.S. Pat. No. 3,810,269, there is disclosed, among other things, a method for producing air ions. In this patent there is also taught which ions are to be designated as "air ions" and the frequency as well as the concentration with which such normally occur. In a more general manner and for purposes of understanding the present invention it may be stated that under the expression "air ions" there is to be understood molecules of the gases (also water vapor) present in air, at the other shell of one or more atoms of which there can be removed or added one or more electrons by supplying energy, which, however, are not disassociated. In the context of the foregoing there thus should be primarily understood such ions under the expression "air ions." Further, it should be understood that during their production it is impossible to avoid the formation of a certain quantity of ozone. In any event an air ion is a particle having a comparatively high electrical potential.